Protective ensembles are used in the field of civilian safety or in industry, for example in the nuclear or chemical industry to insulate a person from a hostile outside environment.
In the nuclear industry, persons are led to ensuring the maintenance of equipment or to conducting tasks in contaminated environments, contaminated in particular by radioactive particles. Under these conditions, such persons must be encapsulated in a protective suit to avoid any contact between the skin and radioactive particles and they must not breathe in any outside contaminated air.
Having regard to the long duration and complexity of some operations carried out by such persons, it is important that the wearing of this suit should be ergonomic and comfortable. In addition, it must be possible for the donning and fitting of the suit as well as the removal thereof to be performed simply and relatively quickly.
A protective ensemble is known from document FR 2 793 147. It comprises a sealed suit fed with air to allow ventilation and therefore the lowering of the temperature inside the suit. This provides increased comfort for the wearer in particular in the event of prolonged used of the protective garment.
Also, air is fed via a flexible air intake to a mask held to the wearer's face by means of supporting straps.
Another protective ensemble is described in document US 2004/0226558. It is in the form of a suit comprising in particular a part that forms a hood and means for connection to a source of compressed air. The compressed air is guided firstly into the inner volume of the hood and secondly into the other parts of the suit to ensure the ventilation thereof.
The wearer is therefore not obliged to wear a mask since it is possible directly to breathe the air contained in the hood. The air flow rate is adjusted so that there is sufficient air renewal to avoid a substantial increase in carbon dioxide within the hood.
In addition, only one air feed can be used, which allows simplification of the use of the said protective system.
In this case however, should there be pressure be drop in the air supply network, this will give rise to risks for the wearer being ill-supplied with air. There may a sudden increase in the carbon dioxide level inside the hood volume which, within a few instants, may exceed a critical threshold placing the wearer in danger.